Stabilization of the resistive wall mode by differentially rotating walls

The effect of differentially rotating walls on external resistive wall instabilities is investigated for a general cylindrically symmetric diffuse pinch configuration. It is found that when the relative wall rotation velocity exceeds a critical value, the resistive wall mode is stabilized. The critical rotation frequency is, however, quite large, well above the growth rate with a single wall and probably impractical for a realistic experiment. Though the presence of a finite vacuum gap between the walls reduces the critical velocity for stabilization, the required flow is still likely to be too large for practical applications. (C) 2001 American Institute of Physics.